JPH06115995A - Concrete composition for self-filling - Google Patents

Abstract

PURPOSE:To secure the high flowability, high chargeability, high aggregate separation resistance and high strength of the concrete composition by adding a high performance water-reducing agent and a specific water-soluble polymer. CONSTITUTION:A naphthalene sulfonate metal salt-formaldehyde condensation product, a melamine sulfonate metal salt-formaldehyde condensation product, etc., are used as the high performance water-reducing agent to be an effective component in an amount of 0.3-3.0wt.% based on a cement. The water-soluble polymer includes acrylic acid, alkylene oxide, amide, cellulosic beta-glucan, starchy, polymers and polyol polymers. The water-soluble polymer has an average particle diameter of 1-300mum and is added to the concrete composition in an amount of 0.01-2.0wt.%. Other cement additives such as an air-carrying agent and a gypsum anhydride strength-enhancing agent can further simultaneously be used. The use of the composition gives a slump flow value of >=40cm. The cement mixed with the cement additive can be cured by a conventional method, and a steam curing method or an autoclave curing method may also be used.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a self-compacting concrete composition which does not require compaction. More specifically, the present invention relates to a self-compacting concrete composition which has a property of enhancing the viscosity and fluidity of concrete used as a construction material and a secondary product material and having excellent resistance to separation of aggregate, cement and water.

[0002]

2. Description of the Related Art Conventionally, as a conventional method for constructing a concrete composition, it is general to put concrete into a form frame having reinforcing bars and to perform compaction by vibrating a vibrator. is there. However, in recent years, the noise pollution caused by a vibrator when placing concrete and the shortage of manpower in the concrete industry have become serious problems. In the secondary product field, construction materials such as building boards are becoming thinner and bar reinforcement is becoming denser, making it difficult to perform construction that relies on vibrators.

To address these problems, research on concrete having self-filling properties has begun, but at present it is technically not yet in practical use.

Generally, when the fluidity of concrete is increased, the aggregate is separated, and the aggregate is occluded between the reinforcements and between the reinforcements / forms. As a result, the filling property is lowered and the concrete composition is made non-uniform, and the concrete strength is lowered. In addition, in concrete mixes with thickeners such as underwater concrete, although the separation of aggregates is suppressed, a significant delay in the curing time, which is the property of thickeners, and the slow development of initial strength It is difficult to apply it to civil engineering, especially to factory products.

In recent years, a compaction-free concrete composition reported under the name of high-performance concrete (Journal of Japan Society of Civil Engineers, October 1989) is a composition containing blast furnace slag, fly ash and a thickener, and It has an improved set time over concrete. However, since the amount of thickener used is large, it causes a delay in curing, has a low demolding strength, and is difficult to use in civil engineering, building structures and factory products that require initial strength, and also causes cost increase. ing.

Conventionally, a water-soluble polymer has also been used as an additive, but it is used by adding it in the form of an aqueous solution or powder. However, the water-soluble polymer is not only highly viscous in an aqueous solution and difficult to add, but also has a strong aggregating effect during the initial production of concrete, making it difficult to obtain sufficient fluidity. On the other hand, in the conventional powder addition, the water-soluble polymer remains in the concrete in an undissolved state, and more water-soluble polymer than necessary is added to the concrete. However, this excess water-soluble polymer causes concrete to swell / dissolve gradually during hardening, which causes retardation of hardening, and in the case of large particles, also causes defects due to localization.

[0007]

[Means for Solving the Problems] The present inventors added a high-performance water-reducing agent and a water-soluble polymer having an average particle size of 1 to 300 μm in combination to obtain a slump flow value (specified in JIS-A 1101). ) Is 40 cm or more, it is possible to complete a self-compacting concrete composition which is excellent in material separation resistance, has self-filling property, and has little hardening delay.

That is, according to the present invention, a slump flow value (specified in JIS-A 1101) obtained by adding a high-performance water reducing agent and a water-soluble polymer having an average particle diameter of 1 to 300 μm is 40 cm or more. The invention relates to a self-compacting concrete composition characterized by:

In the present invention, the self-compacting concrete composition means concrete having a slump flow value of 40 cm or more in the slump test specified in JIS-A 1101.

The high-performance water reducing agent in the present invention means a naphthalenesulfonic acid metal salt formaldehyde condensate [for example, Mighty 150: manufactured by Kao Corporation] or a melamine sulfonic acid metal salt formaldehyde condensate [for example, Mighty 150V-2: Manufactured by Kao Corporation. Further, as a high-performance water reducing agent, a formaldehyde condensate of one or more compounds selected from the group of methylol compounds and sulfonate compounds of melamine, phenol, urea and aniline, for example, phenolsulfonic acid formaldehyde condensate (Patent No. .1097647), phenol-sulfanilic acid formaldehyde co-condensates (compounds described in JP-A 1-113419), unsaturated monocarboxylic acids and their derivatives, unsaturated dicarboxylic acids and their derivatives Polymers or copolymers obtained by polymerizing one or more monomers selected from the group (Japanese Patent Publication No. 2-7901).
JP-A-3-75252, JP-B-2-8983, etc.). The amount added is effective for cement
It is preferable to add 0.3 to 3.0% by weight.

The water-soluble polymer in the present invention includes acrylic acid type, alkylene oxide type, amide type, cellulose type, starch type, polyol type and the like. Acrylic acid type, polyacrylic acid, sodium polyacrylate, potassium polyacrylate, alkylene oxide type, polyethylene oxide, amide type, polyacrylamide, cellulose type, β-1,3-glucan, methyl cellulose, hydroxyethyl cellulose , Guar gum, xanthan gum, pullulan, carrageenan, tamarind gum, starch-based modified starch, partially hydrolyzed starch, partially-crosslinked starch, and polyol-based polyethylene glycol, polyvinyl alcohol, etc., but not limited to these. Not something. The water-soluble polymer can be atomized by direct synthesis such as emulsion polymerization or by a pulverizer. The crusher is not particularly limited as long as it can crush to a suitable particle size, such as a sand mill or a ball mill. The average particle size of the water-soluble polymer is 1 to 300 μm, and if it is 1 μm or less, the dissolution rate is fast and the product stability is poor due to dissolution in the product slurry. This state) occurs and sufficient separation resistance cannot be obtained. On the other hand, if it is 300 μm or more, a sufficient dissolution rate cannot be obtained. The amount of water-soluble polymer added is 0.01 to 2.0 based on the weight of cement.
% By weight, preferably 0.05 to 1.0% by weight. 0.
If it is less than 01% by weight, no effect is obtained, and if it is more than 2.0% by weight, sufficient fluidity cannot be obtained, which causes a delay in curing. The addition method is not particularly limited, such as during kneading and after kneading. There are several addition forms such as powder and slurry.

The self-compacting concrete composition of the present invention comprises other cement additives (materials) such as air entraining agents, anhydrous gypsum-based strength enhancers, activated silica fine powders, waterproof materials, water reducing agents, and high water solubility. It can also be used in combination with molecules, drying shrinkage reducing agents, fluidizing agents, waterproofing agents, expanding agents (materials), glass fibers, steel fibers, stone powder, fly ash, blast furnace slag and the like.

In the production of a hardened cement product to which the cement admixture according to the present invention is added, the curing method may be a method of hardening a usual hardened cement product, such as steam curing or autoclave curing. You may use.

Hereinafter, the present invention will be further described with reference to examples.

[0015]

EFFECTS OF THE INVENTION According to the self-compacting concrete composition of the present invention, it becomes possible to secure high fluidity, high filling property, aggregate separation resistance, and strength. The method has been dramatically improved, and especially in the production of concrete products, it has a large ripple effect on noise reduction and production rationalization.

[0016]

EXAMPLES The present invention will be described below with reference to production examples and examples of the present invention, but the present invention is not limited to these examples. The percentages in the following examples are weight percentages.

(Material) Cement (C): Normal Portland cement (specific gravity 3.17) Fine aggregate (S): Kinokawa sand (specific gravity 2.57, FM 2.91) Coarse aggregate (G): Takarazuka crushed stone (specific gravity 2.61, FM) 6.34) Blast furnace slag (SL): specific surface area 8,000 cm ² / g, specific gravity 2.90 (mixing) Table 1 shows the mixing composition of the concrete composition prepared by using the above materials.

[0018]

[Table 1]

(Method of mixing concrete) A cement dispersant was dissolved in mixing water in advance, and 50 liters of concrete was mixed for 2 minutes at 20 ° C using a 100 liter tilting mixer, followed by slump flow. Aggregate separation resistance was measured. The slump flow test was performed according to JIS-A 1101.

Next, sodium naphthalenesulfonate formaldehyde condensate (trade name: Mighty 150, manufactured by Kao Corporation) was added to the composition shown in Table 1 as a high-performance water reducing agent.
Β-glucan was used as a water-soluble polymer. The obtained results are shown in Table 2.

[0021]

[Table 2]

From Table 2, the concrete composition of the present invention shows high fluidity with a slump flow value of 40 cm or more and good separation resistance. If the added amount of the high-performance dispersant and the average particle size and added amount of the water-soluble polymer are outside the scope of the present invention, either fluidity or separation resistance cannot be secured, and sufficient self-compacting concrete cannot be obtained. Can be confirmed.

Table 3 shows the results of adding the above-mentioned high performance water reducing agent and other water-soluble polymer to the composition of Table 1. The amount of water-soluble polymer added was all 0.1%, and the measuring method was the same as above.

[0024]

[Table 3]

The composition of Table 1 and the superplasticizer of Table 4 and β-
The results of adding glucan are shown in Table 5. The measuring method is the same as above.

[0026]

[Table 4]

[0027]

[Table 5]

From Tables 3 and 5, the slump flow values are
It exhibits high fluidity of 40 cm or more and has good separation resistance.

Claims (3)

[Claims] 1. A high-performance water reducing agent and an average particle size of 1 to 300 μm
Slump flow value obtained by adding water-soluble polymer of
A concrete composition for self-filling, characterized by having a (JIS-A 1101) of 40 cm or more. 2. The self-compacting concrete composition according to claim 1, wherein the amount of the water-soluble polymer added is 0.01 to 2.0% by weight based on the weight of the cement. 3. The self-compacting concrete composition according to claim 1, wherein β-glucan is used as the water-soluble polymer.